Take a stout Bass casting rig with you with a heavy huge spoon on it next time. If someone approaches too close just pick it up and start casting in the direction you need to. You might actually catch something and it will deter all but the most ignorant. And you can do it legitimately fishing...you may not do it otherwise but hey if you just sincerely fish it hard for as long as it takes nobody can fault you for that. And you don't have to do it as an obvious attempt to divert people...just get serious with that thing for a while and if they pass close enough just tell them all the big bass you been catching on that thing...A little George works good too and I have slammed some big fish working either around a good ledge.